Throughout his known history, man has used a variety of mediums from which to fabricate his shelter, including earth. An increasing awareness of energy usage and waste has inspired a resurge of interest in earth-sheltered structures. As used herein, "earth-sheltered" refers not only to underground housing, but also to structures built above ground that have at least the roof and one side substantially sheltered by a layer of earth.
Constructing an earth-sheltered structure requires the builder to take into consideration certain factors not usually present in ordinary construction. The layer of earth used to shelter and insulate the structure not only increases the ordinary stress that the structure must withstand, but also introduces significant stresses from directions not ordinarily encountered when building a non-earth-sheltered structure. Because of this, the builder should not simply strengthen an ordinary above-ground structure and assume that it will serve suitably as an earth-sheltered structure.
To meet these considerations, the construction industry has generally relied upon concrete foundation walls to support earth-sheltered structures. Although such foundations have proven to be structurally sound, they present other problems for the builder. Most importantly, perhaps, such foundations are relatively expensive and time-consuming to build and generally require a significant amount of on-site preparation and expertise. Concrete foundations also contribute to an undesirable humid atmosphere in the structure.
The remaining structural members that contribute towards supporting the structure in earth-sheltered structures of the prior art include other important non-wood elements as well. For instance, metal beams, metal strapping and fiberglass sheer walls have all been relied upon in various earth-sheltered structures to assist in supporting both the structure and the layer of earth. Unfortunately, such items may be difficult to obtain at times, and may otherwise necessitate inconvenience in their obtainment and installation.
There therefore exists a need for a structurally sound, low cost earth-sheltered structure that may be easily and quickly erected with a minimum of on-site expertise.